[Possible mod] Pixel 3 Fast Wireless Charge

[k0rner]

Pixel 3 enables fast (>5W) wireless charging only on Google certified chargers, and there are only a few of them.
On most QI-compatible chargers it will pull out max ~750mA charging current by default (checked by Ampere / 3C Toolbox and simialr apps)
However, there is an interesting control file in /sys/class/power_supply/wireless, voltage_max.
It has default value of 5000000 (5V), and you can write values of up to 9000000 into it (9V), which surprisingly is accepted and leads to more charging current.

However, this should be done while wirelessly charging (as file does not accept writes otherwise).

echo 9000000 > /sys/class/power_supply/wireless/voltage_max
# Now, check what we've got
grep . /sys/class/power_supply/wireless/voltage_*
voltage_max:9000000
voltage_now:8568000 # Means it has been raised by device

After such write, charging current can be as high as 1290mA (compared to 700-750mA stock).

This change reverts after the end of charging session, however.

Question to kernel devs around here - can this be made permanent in some of custom kernels, or have a SysFS switch like "USB3 fast charge"?
The issue is to find where the default value is stored and alter it there.

EDIT Currently this can be made permanent by means of Magisk module "Advanced Charging Control" (https://xdaforums.com/apps/magisk/module-magic-charging-switch-cs-v2017-9-t3668427),
by adding the following to config:

onPlugged=./wireless/voltage_max:9000000

 

[sliding_billy]

Nice find. Given how many folks are ending up with useless Pixel 3 and 3XL devices after using off-brand wireless chargers I am hesitant to use one even with the Google empowered limiters.

 

[MishaalRahman]

Have you verified that the charging speed actually increases?

 

[k0rner]

Have you verified that the charging speed actually increases?

Yes, battery charging current reported by Ampere app is higher. And the battery charges faster (in % per minute)

 

[MishaalRahman]

Can anyone else verify?

 

[Aaron1017]

Confirmed it does indeed charger faster using a Samsung wireless fast charger and a cheap $6 ebay chinese wireless charger. Enabling 9V DOES cause some slightly audible "ticking" noises every second when playing ear next to charger. Normally its completely silent.

 

[kdrag0n]

I've added this to Proton Kernel as part of the standard "USB fast charge" option that EXKM, Kernel Adiutor, and FKM can tune. It's disabled by default, but please read the following disclaimer thorougly before enabling it:

Think twice before enabling fast wireless charging because cheap chargers can cause your phone to heat up significantly, harming the battery permanently. They may also cause temporary issues with your phone (such as ticking sounds) or permanent damage to internal circuits. However, if used properly with a high-quality charger, there should not be any issues. Enable at your own risk. I am not responsible for any damage to you or your phone caused by this feature.

That being said, several users have gotten good results after enabling it. It's ultimately a question of how cheap your charger is.

 

[ManthanRB]

After such write, charging current can be as high as 1290mA (compared to 700-750mA stock).

I am not sure how true is this, my Pixel 3 charges at 1850mA by default without any modification thru wireless charger and 2900 mA with a wired charger. I am using Pixel stand and Pixel 3 charger.

 

[kdrag0n]

I am not sure how true is this, my Pixel 3 charges at 1850mA by default without any modification thru wireless charger and 2900 mA with a wired charger. I am using Pixel stand and Pixel 3 charger.

This is for non Pixel Stand owners to get closer to the speed of a Pixel Stand.

 

[acidspider]

If possible for fast charge now, can someone locate the trigger for the special pixel stand charging dock screen?

 

[k0rner]

If possible for fast charge now, can someone locate the trigger for the special pixel stand charging dock screen?

That needs someone with the Pixel Stand (e.g. not me) to investigate.
Or, at least do the following while the phone is on the stand, in the terminal:

su
cd /sys/class/power_supply/wireless
grep . *

and post the output here.

 

[fronc]

Does anyone know the safe/recommended wireless charging temperature range? I want to do some comparisons of different wireless chargers I own and see if they're within tolerance. Thanks!

EDIT: Actually, if anyone can tell me what the Google Pixel stand normally gets the temperature up to, then I'll have a benchmark for comparison. Thanks!

 

[lohanchien]

Does anyone know the safe/recommended wireless charging temperature range? I want to do some comparisons of different wireless chargers I own and see if they're within tolerance. Thanks!

EDIT: Actually, if anyone can tell me what the Google Pixel stand normally gets the temperature up to, then I'll have a benchmark for comparison. Thanks!

I'm getting the phone and stand tomorrow. I'm interested in this mod so I'll check the temps and keep you posted

 

[fronc]

I'm getting the phone and stand tomorrow. I'm interested in this mod so I'll check the temps and keep you posted

Awesome. This will be very helpful information for the community! Thanks!

 

[lohanchien]

Awesome. This will be very helpful information for the community! Thanks!

Trying to prepare for this test. I only know of one app that can chart temperature over time but it only allows 200 data points so I'll have to set the refresh rate at 30s which will allow 1.6hrs of recording. I'll have to test from 50% to full and hopefully that'll give enough data. I wanted to test from 1% to full charge but that would mean I have to set the refresh interval to close to 2min, which would wash out temperature fluctuations during those two minutes. Do you know of any app that can chart temperature over time with more than 200 data points?

 

[fronc]

Trying to prepare for this test. I only know of one app that can chart temperature over time but it only allows 200 data points so I'll have to set the refresh rate at 30s which will allow 1.6hrs of recording. I'll have to test from 50% to full and hopefully that'll give enough data. I wanted to test from 1% to full charge but that would mean I have to set the refresh interval to close to 2min, which would wash out temperature fluctuations during those two minutes. Do you know of any app that can chart temperature over time with more than 200 data points?

I do not, but I think that should be sufficient. Maybe a second test from 0 to 50% some other time would be useful as well.

Sent from my Pixel 3 XL using Tapatalk

 

[lohanchien]

I do not, but I think that should be sufficient. Maybe a second test from 0 to 50% some other time would be useful as well.

Yeah I can try that too. But I wanted to see how it behaves over the whole range. It's possible if going from 1 to full might give higher temperatures since the cells will be heated for longer. I guess I'll test 1-50 then 50-100 at 30s then another test 1-100 at two min intervals.

Edit: Miscalculated, 60s from 1-100 should be enough. That's more than 3 hrs. I doubt it'll take that long to fully charge

 

[Bingley]

Trying to prepare for this test. I only know of one app that can chart temperature over time but it only allows 200 data points so I'll have to set the refresh rate at 30s which will allow 1.6hrs of recording. I'll have to test from 50% to full and hopefully that'll give enough data. I wanted to test from 1% to full charge but that would mean I have to set the refresh interval to close to 2min, which would wash out temperature fluctuations during those two minutes. Do you know of any app that can chart temperature over time with more than 200 data points?

Could you ask the dev for a custom modded apk to increase to 400 data points?

 

[jd1639]

That needs someone with the Pixel Stand (e.g. not me) to investigate.
Or, at least do the following while the phone is on the stand, in the terminal:

su
cd /sys/class/power_supply/wireless
grep . *

and post the output here.

capacity:83
current_max:1100000
current_now:1022000
grep: device: Is a directory
online:1
grep: power: Is a directory
present:1
serial_number:e0adc0f6
grep: subsystem: Is a directory
temp:3220
type:Wireless
ueventOWER_SUPPLY_NAME=wireless
ueventOWER_SUPPLY_PRESENT=1
ueventOWER_SUPPLY_ONLINE=1
ueventOWER_SUPPLY_CURRENT_NOW=1022000
ueventOWER_SUPPLY_CURRENT_MAX=1100000
ueventOWER_SUPPLY_VOLTAGE_NOW=8914000
ueventOWER_SUPPLY_VOLTAGE_MAX=9000000
ueventOWER_SUPPLY_TEMP=3220
ueventOWER_SUPPLY_SERIAL_NUMBER=e0adc0f6
ueventOWER_SUPPLY_CAPACITY=83
voltage_max:9000000
voltage_now:8914000
:/sys/class/power_supply/wireless #

Sent from my [device_name] using XDA-Developers Legacy app

 

[lohanchien]

Started the first test. Going from 50-100 with case off and pixel stand app cycling through photos. Next I'll go with the same but turn off photos and leave just the clock in ambient mode. I'll then test the same as the first two with case on. So far it's charging at 1%/min so I set the refresh interval to 15sec. That'll give 50min of data, just enough for the full charge from 50%